1. Field of the Invention
The invention relates to a transport anchor to be embedded in prefabricated reinforced concrete parts such as slabs, supports, rings, boxes etc. The transport anchor comprises a shaft portion that can be anchored within the concrete and a shaft portion which projects from the concrete and has an engagement head which, during casting of the concrete, is surrounded by a removable recess member while the shaft portion that can be anchored within the concrete comprises a support having spacer projections maintaining a spacing to a formwork wall.
2. Description of the Related Art
It is known to use transport anchors of the aforementioned kind for lifting and transporting prefabricated reinforced concrete parts. These transport anchors are added to the reinforcement arrangement before casting the concrete and are anchored in the concrete after casting and curing of the concrete. In this respect it is known to use a recess member during casting of the concrete in order to prevent the shaft portion having the engagement head from projecting past the surface of the prefabricated concrete part. This recess member must be removed after casting and curing of the concrete in order to connect a lifting element to the now exposed engagement head of the shaft portion of the transport anchor. This lifting element, in turn, makes it possible to connect a crane hook etc. In this connection, the recess member is comprised of an elastic material such as, for example, rubber, and cannot be removed in a simple way from the cured concrete. Since the removal of the recess member from the concrete as well as the recess member itself incur costs, it is desirable to reuse the recess member several times. However, this is often not successful because the recess member is destroyed under deformation when removed from the concrete and pulled off the engagement head of the shaft portion.
It is an object of the present invention to improve a transport anchor of the aforementioned kind such that the recess member can be removed in a simple way from the transport anchor and is made of inexpensive material.
In accordance with the present invention, this is achieved in that the engagement head of the projecting shaft portion is surrounded by shell parts which complement one another to form a prism-shaped formed member onto which the recess member can be placed with its hub portion.
By employing two shell parts which complement one another to form a formed member, the recess member surrounding the shell parts can be easily pulled off in the upward direction because an interlocking engagement with the engagement head of the shaft portion of the transport anchor projecting from the concrete cannot occur, and, moreover, the shell parts can be taken off in a simple way in the radial direction once the recess member has been removed.
It is conceivable to design the shape of the engagement head of the shaft portion of the transport anchor to be embedded as well as the shape of the recess member in different ways. For example, the recess member can have the shape of a cube, a truncated cone etc., while the engagement head itself could be a rectangular or square plate or also in the form of an annular member. Preferably, the shaft and the engagement head, however, are cylindrical wherein the engagement head is a disc having a disc diameter which is greater than the diameter of the shaft. In this connection, the formed member surrounding the engagement head is advantageously comprised of two semi-circular ring-shaped shell parts which are surrounded by the hub portion of the recess member positive-lockingly and frictionally during the casting of the concrete.
According to a further feature of the invention, each semi-circular ring-shaped shell part has semi-annular support ribs projecting toward the shaft portion and contacting the shaft portion and also a semi-annular stop which engages the rim area of an end face of the shaft portion in order to prevent canting, i.e., to provide a stabilizing action for an axis-parallel position of the formed member on the engagement head of the transport anchor. In this connection, the recess member is advantageously formed as a semi-spherical open shell having an inner surface from which the cylindrical hub portion projects inwardly. The hub portion rests with its inner end face against the semi-annular stops of the shell parts.
In order to be able to employ the transport anchor not only on a horizontally extending formwork but also on a vertically extending formwork wall, the end face of the cylindrical hub portion of the recess member is provided with a preferably central bore by which the recess member can be fastened to a vertically extending wall by means of the screw. Subsequently, the engagement head of the transport anchor surrounded by the shell parts can be inserted into the hub portion of the recess member so that the transport anchor can project into the area where the concrete is to be cast. The hollow space which is formed by the recess member can be closed in that a lid is placed onto the side of the recess member opposite the hub portion. For the purpose of facilitating detection of the transport anchor in the cast concrete, this lid may comprise at least one, preferably however several, elastic indicator pins on the external side. These elastic indicator pins will stand up after smoothing a horizontal concrete surface so that it is easily recognized at which location a transport anchor is positioned within the concrete.
Especially for the purpose of placing the transport anchor onto a horizontally extending framework plate, the support of the transport anchor is advantageously formed of a receiving box with support fingers projecting away therefrom. A support disc which is connected to the shaft portion that can be embedded in the concrete is secured on the receiving box. In this connection, the support disc of the shaft portion to be embedded in the concrete is advantageously resting with its underside against the bottom of the receiving box, while the upper side of the support disc is spanned by securing bolts which are secured in the sidewalls of the receiving box and rest against the upper side. The support fingers of the receiving box which rest against a wall of the formwork are advantageously provided at their underside with at least one spacer projection which is configured to receive plug-in spacer members so that the position of the engagement head of the transport anchor can be adjusted to the respectively required thickness of the concrete elements.